Question 1. Create a layout of the contour map, overlay points file, “points.shp” (complete with cartographic elements), print it out, and hand draw watershed delineations. Draw a line from basecamp to mountain pick (outlook), selecting the shortest, but the flattest route. Submit this copy to the TAs. 8/9

Question 2. Why is it necessary to fill sinks in the DEM before delineating watersheds?

The reason for filling the DEM is because the sink will make it so that the flow of the water will be messed up. IF there is a null value then it will casue a stop in the Flow and the delination of the watershed and cause error and the stream beds not being connected.

Question 3. How many directions are assigned when running the flow direction operation? How do you think this might influence the resulting delineation? The was 456 directions assigned for the flow direction operation. This would affect the delineation by causing points wher it could go either way to increase. -1 - 8 possible directions, “D8 algorithm” - D8 will result in the delineation not being perfectly accurate because it unfortunately simplifies the complex movement of water in an infinite number of directions. The more detailed the flow direction, the more likely the delineation will be accurate.

Question 4. On your flow accumulation layer, click on the in-stream point labeled "gauge". What is the value? How much area drains into that point? the value is 6917 and this if for 1509 mt area. - pixel value: 6928 - drainage area: 6928*100=692,800m2

Question 5. Make two stream networks: one with threshold value 500 and name that “str_500”; and the other with threshold value 2000 and name that “str_2000”. What is the effect of changing the stream definition threshold? What does this suggest about the Horton stream order concept? The one with 2000 is smaller streams. The higher order streams show up when using str 2000 and while the lower order ones are showing along with the higher orders in the 500. - The lower threshold value produces a more extensive network of streams and the higher threshold value produces a more simplified version. - Horton’s Law of stream orders provides an accurate representation of how water flow volumes in a river are converged when two streams converge. - the drainage area increases as the stream order increases

Question 7. What is the area of your defined subwaterhsed which has “gauge” as an outlet point in both “Catchment_500” and “Catchment_2000” watersheds? Are they same or different? How does this area compare to the value of accumulation discussed in question 4? they are different. The catchments for the 2000 are larger. So the streams in the 2000 catchemnts are larger. - for cat_2000: 694,799 m2. It’s similar to the drainage area in Question 4, 692,800m2. - cat_500 shows more fragmented subwatershed.

Question 8. Create two layouts of the resulting watershed delineation with the DEM, stream and point data (complete with cartographic elements). Explain the difference between the two subwatershed maps. The difference is the stream orders represented and the size of the areas taken into consideration in the delineation.